An evaluation of leukocyte esterase activity as a rapid screening test for significant bacteriuria in children

Abstract

The diagnosis of UTI is usually confirmed by microscopy and culture of properly collected urine specimens; however, due to scarce resources and other limitations, this is often not practicable in many resource poor nations. Since UTI if not identified early and treated could lead to serious complications, this study was therefore carried out to ascertain the clinical importance of Leukocyte esterase (LE) enzyme as a diagnostic tool for screening of Urinary Tract Infections (UTIs) in resource poor countries. The study was cross-sectional in nature comprising 250 asymptomatic pupils (120 males and 130 females) drawn from five nursery schools in Ikot Ansa in Calabar municipal area council in Nigeria. Subjects were selected using computer assisted random sampling methods. Urine specimens were collected, stored, transported, cultured and processed using standard laboratory procedures, while leukocyte esterase (LE) dipsticks were used as a screening tool for UTl and results compared with culture positive results. Significant bacteriuria through culture was recorded in 14 (5.6%) pupils and the commonest bacteria recovered were Escherichia coli 42.9% (6),Proteus mirabilis 21.5% (3) and Klebsiella pneumoniae 14.5% (2). Leukocyte esterase dipstick test correctly identified positive urine culture in 10 of 14 proven UTI (71.4%). The positive and negative predictive values were 25 and 98.1%, respectively. Leukocyte esterase test, though it has limitations in diagnosing UTI when compared to the culture methods, still proves useful in communities without facilities and requisite personnel for urine culture. The test is recommended for use in result limited communities, but where feasible, urine culture should be done. Key words: Children, leukocyte esterase, screening, urinary tract infection.